1. Field of the Invention
The present invention generally relates to balanced transmission connectors, and more particularly, to a balanced transmission connector with a cable which is applied for a part of the balanced transmission of data and connects a computer with a peripheral device.
2. Description of the Related Art
A cable and connector unit, in which connectors are connected with both ends of the cable, is used for connecting a personal computer with a peripheral device. Data are transmitted between the personal computer and the peripheral device, by connecting respective connectors which are at the respective ends of the cable with the personal computer and the peripheral device.
There are two methods as data transmission methods. One is a normal transmission method and the other is a balanced transmission method. In the normal transmission method, one electric wire is used for every datum. Contrary, in the balanced transmission method, a pair of electric wires are used for every datum. A xe2x80x9c+xe2x80x9d signal to transmit and a xe2x80x9cxe2x88x92xe2x80x9d signal are simultaneously transmitted in the balanced transmission method. A magnitude of the xe2x80x9cxe2x88x92xe2x80x9d signal is equal to that of the xe2x80x9c+xe2x80x9d signal. A direction of the xe2x80x9cxe2x88x92xe2x80x9d signal is reverse to that of the xe2x80x9c+xe2x80x9d signal. Use of the balanced transmission method is on the increase for data transmission because the balanced transmission method has an advantage in that it is more robust against a noise than the normal transmission method.
With the recent development of personal computers and networks thereof, systems are required for transmitting a large amount of data of, especially, moving pictures, video images, or the like. In order to transmit a large amount of dynamic image data, it is necessary to transmit data at a high data transmission rate, more than 1 gigabit/sec.
In case of that the data transmission is implemented at high rate such as more than 1 gigabit/sec, a wavelength of the signal is short. Therefore, an electromagnetic wave occurring in an inside of the connector can easily leak to outside of the connector. Thus, it is necessary to take measure as to an electromagnetic interference (EMI) for a balanced transmission connector with a cable.
An applicant of the present patent application filed a Japanese patent application, which was published as a Japanese Laid-Open Patent Application No. 2000-068007, xe2x80x9cBalanced-Transmission Cable-And-Connector Unitxe2x80x9d. In this patent application, a balanced transmission connector with a wire has a structure in which a plug for a balanced transmission is inserted in a shield cover assembly. The plug for a balanced transmission has a structure in which the pair of the first and the second signal contacts and the ground contact having a board shape are arranged in turn at predetermined intervals in a block made of synthetic resin.
FIGS. 1A and 1B are views showing a conventional shield cover assembly. Referring to FIG. 1A, a shield cover assembly 140 includes a first half shield cover 141 and a second half shield cover 145 connected together. Flat-surface edges of side wall parts 142 and 143 of the first half shield cover 141 are in contact with flat-surface edges of side wall parts 146 and 147 of the second half shield cover 145.
Referring to FIG. 1B, a shield cover assembly 150 includes a first half shield cover 151 and a second half shield cover 155 connected together. Side wall parts 152 and 153 of the first half shield cover 151 are situated inside side wall parts 156 and 157 of the second half shield cover 155. The side wall part 152 overlaps the side wall part 156. The side wall part 153 overlaps the side wall part 157.
However, in the shield cover assembly 140 shown in FIG. 1A, an xe2x80x9celectric gapxe2x80x9d may be formed partially at positions where the flat-surface edges of the side wall parts 142 and 143 of the first half shield cover 141 are in contact with the flat-surface edges of the side wall parts 146 and 147 of the second half shield cover 145. The xe2x80x9celectric gapxe2x80x9d connects straight the inside of the shield cover assembly 140 with the outside thereof. The xe2x80x9celectric gapxe2x80x9d is defined as a gap having a size through which the electromagnetic wave can pass. Accordingly, the shield cover assembly 140 does not have a sufficient electromagnetic sealability to shield the electromagnetic wave leaking from the inside of the connector to the outside.
On the other hand, the shield cover assembly 150 shown in FIG. 1B has a structure in which the side wall part 152 is covered with the side wall part 156, and the side wall part 153 is covered with the side wall part 157. Accordingly, an xe2x80x9celectric gapxe2x80x9d is unlikely to be formed between the first half shield cover 151 and the second half shield cover 155. Hence, an electromagnetic sealability of the shield cover assembly 150 is better than that of the shield cover assembly 140 shown in FIG. 1A. However, a width L of the shield cover assembly 150 is increased due to the overlap of the side wall parts 152, 153, 156, and 157 as described above. Hence, the shield cover assembly 150 has a disadvantage in that a size of the balanced transmission connector is big.
Accordingly, it is a general object of the present invention is to provide a novel and useful balanced transmission connector in which one or more of the problems described above are eliminated.
Another and more specific object of the present invention is to provide a small-size balanced transmission connector having a sufficient electromagnetic sealability to limit an electromagnetic wave leaking from an inside of a balanced transmission connector to an outside of the connector.
The above objects of the present invention are achieved by a balanced transmission connector, including a relay board, a plug body for balanced transmission provided on an end part of the relay board, a cable for balanced transmission connected with another end part of the relay board, and a shield cover assembly covering the relay board, the plug body for balanced transmission, and a part of the cable and including a first half shield cover having side wall parts, an edge of which has a step-shaped surface including a base flat surface and a raised flat surface extending in parallel and in a longitudinal direction of the edge, the base flat surface positioned on an interior side of the side walls, and a second half shield cover having side wall parts, an edge of which has a step-shaped surface including a base flat surface and a raised flat surface extending in parallel and in a longitudinal direction of the edge, the base flat surface of the side walls of the second half shield cover positioned on an exterior side of the side walls, wherein the raised flat surface of either one of the first and second half shield covers is in direct contact with the base flat surface of another one of the first and second half shield covers in an engaged position in which the first half shield cover and the second half shield cover are connected together. Alternatively, a shield cover assembly may include a first half shield cover which includes a side wall part having an edge, a second half shield cover which includes a side wall part having an edge which faces to the edge of the side wall part of the first half shield cover, a concave part which is formed on the edge of the side wall part of either first or second half shield cover and extends in an longitudinal direction of the side wall part, and a convex part which is formed on the edge of the side wall part of another half shield cover, clamps the concave part and extends in an longitudinal direction of the side wall part, thereby the first half shield cover and the second half shield cover can be connected together.
According to the above invention, it is possible to insure that there is no xe2x80x9celectric gapxe2x80x9dbetween the first and second half shield covers, by contacting the end edges of the side wall parts of the respective half shield covers. Also, the generation of xe2x80x9celectric gapsxe2x80x9d between the first and second half shield covers, can be prevented by making all the necessary provisions within the width at a single side wall part. Hence, it is possible to limit the electromagnetic wave leaking from the relay board and the like, without increasing the width of the shield cover assembly.
The first half shield cover may further include an outside wall part having an edge and provided outside of the side wall part of the first half shield cover, and a catching part provided on an head end side of the connector, and the second half shield cover may further include an outside wall part having an edge and provided outside of the side wall part of the second half shield cover, and an end part of a longitudinal direction, wherein the catching part of the first half shield cover catches the end part of the second seal half cover and an end of the cable is screw-fixed with the first half shield cover, thereby the edges of the respective outside wall parts of the respective half shield covers are in contact.
According to the above invention, the catching part of the first half shield cover catches the end part of the second seal half cover and an end of the cable is screw-fixed with the first half shield cover. Hence, the end edges of the respective side wall parts of the respective half shield covers are connected together with a high pressing force.
The first half shield cover may further include an outside wall part having an edge and provided outside of the side wall part of the first half shield cover, and the second half shield cover may further include an outside wall part having an edge and provided outside of the side wall part of the second half shield cover, wherein a height position where the edge of the outside wall part of the first half shield cover is in contact with the edge of the outside wall part of the second half shield cover is different from a height position where the edge of the side wall part of the first half shield cover is in contact with the edge of the side wall part of the second half shield cover.
According to the invention, the outside wall part faces to the position where the end edge of the side wall part of the first half shield cover and the end edge of the side wall part of the second half shield are contacted, so that it may be robust against leaking out of the electromagnetic wave generating in the relay board and the like.
A balanced transmission connector may include a relay board, a plug body for balanced transmission provided on an end part of the relay board including a first signal contact, a second signal contact, a ground contact having a plate shape, a groove for the signal contacts, a slit part having a head end, and a connecting part, a cable for balanced transmission connected with another end part of the relay board, and a shield cover assembly which covers the relay board, the plug body for balanced transmission, and a part of the cable, wherein all or a part of the ground contacts has a convex head part, the first and second signal contacts and the ground contact are arranged in turn at a designated pitch, the first and second signal contacts are inserted into the groove for the signal contacts, the ground contact is inserted and penetrates to the slit part, the slit part has a corresponding configuration to a configuration of the convex head part of the ground contact, and the head end of the slit part is connected by the connecting part.
According to the above invention, the block body has a comb tooth shape because the block body has the slit parts in which a grand contact is inserted. Head end parts of all or a part of a comb tooth parts is connected, so that the mechanical strength of the block body can be kept.
The above objects of the present invention are also achieved by a shield cover assembly, including a first half shield cover having side wall parts, and edge of which has a step-shaped surface including a base flat surface and a raised flat surface extending in parallel and in a longitudinal direction of the edge, the base flat surface positioned on an interior side of the side walls, and a second half shield cover having side wall parts, an edge of which has a step-shaped surface including a base flat surface and a raised flat surface extending in parallel and in a longitudinal direction of the edge, the base flat surface of the side walls of the second half shield cover positioned on an exterior side of the side walls, wherein the raised flat surface of either one of the first and second half shield covers is in direct contact with the base flat surface of another one of the first and second half shield covers in an engaged position in which the first half shield cover and the second half shield cover are connected together.
Furthermore, the above objects of the present invention are achieved by a shield cover assembly, including a first half shield cover which includes a side wall part having an edge, a second half shield cover which includes a side wall part having an edge which faces to the edge of the side wall part of the first half shield cover, a concave part which is formed on the edge of the side wall part of either first or second half shield cover and extends in an longitudinal direction of the side wall part, and a convex part which is formed on the edge of the side wall part of another half shield cover, clamps the concave part and extends in an longitudinal direction of the side wall part, thereby the first half shield cover and the second half shield cover can be connected together.
Other objects, features, and advantages of the present invention will be more apparent from the following detailed description when read in conjunction with the accompanying drawings.